Chinese publication 36KR reports that even though the design may be fanless, meaning the Surface Pro 4 would be whisper-quiet even under heavy loads, the tablet will still come with small holes for heat radiation and dissipation. The holes are said to not be as visible as those on the Surface Pro 3, which uses last year's Intel Haswell processor.

This also means that the Surface Pro 4 would be thinner than the Surface Pro 3 if these speculations are accurate, but the site says that the tablet won't be lighter. The device, like the Surface Pro 3, will use a 12-inch display with the same 2,160 x 1,440-pixel resolution.

Design continuity

Microsoft is said to be keeping the design and the battery on the Surface Pro 4 largely the same as on the Surface Pro 3. This isn't a bad thing for those who have already bought into the Surface ecosystem. It allows existing Surface Pro 3 desktop docks, Type Cover keyboard cases, and chargers to be reused on the Surface Pro 4.

The screen resolution, size and aspect ratio made the Surface Pro 3 a winner, and in Microsoft's most recent earnings call, the company said that Surface sales increased 44% year-over-year. Keeping the same screen makes sense as the Surface Pro 3 feels roomier than the 10.6-inch display on the prior generation Surface Pro 2. The aspect ratio also feels more natural when the Surface Pro 3 is used as a tablet.

Intel processor

What's still up in the air is the choice of Intel processor given the description of a fanless tablet. Currently, the only Intel CPUs on the market that can accommodate a fanless design is the more power-efficient Atom series processors - which Microsoft is using on the entry level Surface 3 - and the Core M series on the Apple MacBook and Dell Venue 11 Pro 7000 series.

It's unclear if Microsoft will be able to relieve the heat generated by the more powerful Intel Broadwell processor, especially at the higher specification Core i7 level, to achieve a fanless design.

Battery life

All else being equal, the biggest upgrade to users looking to migrate from a Surface Pro 3 to a Surface Pro 4 would be battery life.

Intel claims that Broadwell draws up to 30% less power than last year's Haswell chips, and that users could expect to see about 1.5 hours additional runtime on a charge.

Coupled with a fanless design, or one with a smaller fan that draws less power, the Surface Pro 4 could keep users productive even longer. Battery life on the Surface Pro 3 is rated at nine hours.

With Windows, this means that the Surface Pro 4 could achieve a battery life that's competitive with Apple's iPad, but with more power, access to legacy Win32 programs and enterprise-grade software in a convertible Ultrabook form factor with the optional Type Cover.